Halo Expansion Teaser Trailer; Release Date, Too?

The ominous twelve-hour countdown on Bungie's website has finally finished and now we know what The Big Announcement was: a teaser trailer. Ah, my favorite form of non-information.

The short video, entitled "Keep It Clean," is available below for you to watch and scratch your head at. It's footage of an evacuated, futuristic city - New Mombasa? - being bombarded with some sort of metal pods falling from space. Then a message: "Halo 3 - Prepare to Drop."

The metal pods might be Orbital Drop Shock Troopers, elite human troops that drop into fire zones from orbit. So they're liberating the city, then? From what? Hmm. Last time we saw Master Chief at the end of Halo 3, he was drifting off into space. So will this game not have him as a playable character?

So yeah, some sort of Halo 3 expansion. A new single-player campaign, at that. Good way to ring in the one year anniversary of Halo 3. Feel free to go nuts now.

Update: An eagle-eyed Joystiq reader noticed the date "01/06/09" somewhere in the video. Check out the photo for yourself over at Joystiq...the date is amidst a cluster of other numbers and could be meaningless. Still, January doesn't sound like a far-fetched release date for the expansion.